The present invention relates generally to ice making apparatus and, in a preferred embodiment thereof, more particularly provides an auger type flake ice-making machine which is provided with a uniquely configured evaporator/freezing section that increases the freezing capacity of the evaporator without increasing its physical size.
Auger type ice flaking machines are well known in the ice manufacturing art and typically comprise an evaporator/freezing section operably interposed in a refrigeration circuit additionally including the usual compressor, condenser, expansion valve and suction accumulator. In a conventional form thereof, the evaporator/freezing section has a vertically disposed cylindrical metal flaker barrel having closed upper and lower ends, and smooth outer and inner side surfaces.
During operation of the machine the refrigerant flowing through the refrigeration circuit is used to chill a longitudinally intermediate exterior side surface portion of the flaker barrel while water is being flowed into the interior of the barrel through a lower end portion thereof. The refrigerant chilling of the barrel causes the water to freeze in a thin layer around the interior side surface of the barrel. The spiralled blade of a motor-driven auger member coaxially disposed within the barrel continuously scrapes the ice layer to remove flakes therefrom which are driven upwardly within the barrel and discharged therefrom, in the form of "flake" ice, through a suitable discharge passage or chute positioned on an upper end portion of the barrel. If desired, various devices known as "pelletizers" may be incorporated into the evaporator/freezing section to convert the flaked ice into pelletized form prior to its discharge from the upper end portion of the barrel.
A particularly efficient method of chilling the exterior side surface of the flaker barrel is to tightly wind a length of refrigerant tubing around the smooth longitudinally intermediate exterior side surface portion of the barrel in a helical configuration in which the resulting tubing coils are longitudinally spaced apart from one another. The upper end of the coiled tubing is connected to the refrigeration circuit piping exiting the expansion valve, while the lower end of the tubing coil is left open. The coiled tubing section is encased within an annular jacket structure coaxially secured to and sealed around the longitudinally intermediate portion of the barrel, the jacket having an outlet opening positioned adjacent its upper end and connected to an accumulator inlet pipe portion of the refrigeration circuit.
During operation of the ice flaker, refrigerant discharged from the expansion valve is spirally flowed downwardly through the tubing coil, in a first rotational sense, and is discharged into a lower end portion of the jacket interior through the open lower end of the tubing. The refrigerant discharged from the lower tubing end in this manner is then flowed spirally upwardly through the jacket, in an opposite rotational sense, through the helical flow path defined within the jacket interior by adjacent pairs of tubing coils, and is flowed outwardly through the jacket outlet. In this manner, heat is transferred from the longitudinally intermediate barrel portion to the tubing coil and also to the refrigerant discharged therefrom into the jacket interior.
In conventional ice making machines of this type, as well as in machines employing other barrel-refrigerant heat transfer structures, there is a natural tendency for the machine's freezing capacity to diminish over time due to factors such as lime or scale buildup on the flaker barrel and/or associated water units, and dust and dirt buildups on the condenser. This natural freezing capacity reduction can eventually cause the ice making capacity of the machine to fall below its rated level. In order to compensate for this eventual capacity reduction it has heretofore been necessary to "oversize" the machine by increasing the physical size of the evaporator section - either its length, its diameter or both. This evaporator section oversizing is, of course, undesirable since it increases the overall size, weight and cost of the ice making machine.
It is accordingly an object of the present invention to provide an ice making machine of the general type described above in which the freezing capacity of its evaporator section is substantially enhanced without the conventional necessity of increasing its physical size, or of increasing the chilling capacity of its associated refrigeration circuit.